As in [1]}, we resort to the so called use-and-then-forget
bound to characterize the ergodic rate performance. We rewrite the received signal \(r_k\)  in (REF ) as
\(r_{k}=\underbrace{\sqrt{p} \, \mathbb {E}\left\lbrace \hat{\mathbf {q}}_{k}^{H} \mathbf {q}_{k}\right\rbrace  x_{k}}_{\text{Desired signal }}+\underbrace{\sqrt{p}\left(\hat{\mathbf {q}}_{k}^{H} \mathbf {q}_{k}-\mathbb {E}\left\lbrace \hat{\mathbf {q}}_{k}^{H} \mathbf {q}_{k}\right\rbrace \right) x_{k}}_{\text{Signal leakage }}+\underbrace{\hat{\mathbf {q}}_{k}^{H} \mathbf {n}}_{\text{Noise }}.\) 
